Item of seating furniture

ABSTRACT

An item of seating furniture includes a carrying frame having a carrying element; a seat frame having a seat surface; and a backrest, wherein the carrying element extends into a region of the backrest; a sliding guide, wherein the seat frame is displaceable in the sliding guide relative to the carrying frame between a front working position and a rear resting position. The item also includes a pelvic support disposed in a rear region of the seat surface and inclined in the front working position in relation to a plane of the seat surface; a frame configured to carry the pelvic support and pivotably movable relative and kinematically coupled to the seat frame; a thrust bearing configured to support the frame in a displaceable and pivotably movable manner; and a joint connecting the frame to the seat frame at a trailing end portion of the seat frame.

Priority is claimed to German Patent Application No. DE 10 2009 016 968.7, filed Apr. 14, 2009, the entire disclosure of which is incorporated by reference herein.

The invention relates to an item of seating furniture with a carrying frame and a seat frame which is displaceable in a sliding guide relative to the carrying frame between a front working position and a rear resting position and carries a seat surface, and also with a frame, which is pivotably movable relative to the seat frame and kinematically coupled to the seat frame, for a backrest.

BACKGROUND

An item of seating furniture of this type is already widely used in daily life, in particular in offices, and thus forms part of the prior art on account of obvious prior use. A key aspect of this is the ergonomically beneficial switching between a hollow and a round back during sitting. Supporting of the back in all positions is, in particular, to be allowed. This is achieved by a kinematic coupling of the seat surface to the backrest which is held on a lateral frame element. This frame element is guided in a connecting link guide in such a way that the movement from the working position into the rear resting position leads to a backward inclination of the backrest and at the same time to a lowering of the backrest. In the process, the seat surface is at the same time moved along a substantially horizontal plane.

In addition, the seat surface has at its trailing end a vertically upwardly directed angled portion which is positioned parallel before the backrest in the working position, but encloses an acute angle with the backrest in the resting position. A cushion, which is connected both to the backrest and to this angled portion, thus experiences an additional inclination which differs from the actual backrest.

DE 10 2007 012 728 A1 relates to a passenger seat for vehicles, in particular railway vehicles, with a seat part and a backrest, the seat part being displaceable in relation to a base frame, which is common with the backrest, in the longitudinal direction of the seat part. In this case, a forward displacement of the seat part provides at the same time a backwardly directed arching of the backrest in the lumbar vertebral region as a support for a kyphosis position of the back, so that the entire seat part surface is also still available, although the lower part of the backrest cushion is pulled forward. Likewise, in a passenger seat of this type, a backward displacement of the seat part at the same time intensifies the arching of the backrest in the lumbar vertebral region as an intensified lordosis support, as the backrest cushion has in the lumbar vertebral region a backwardly directed projection or an arching which then presses against a part of the base frame in the backrest region and thus causes a forwardly directed arching of the backrest cushion.

DE 10 2006 056 928 B3 relates to a seat with a seat panel and a backrest, the seat panel being connected by a first connecting means to a base means and adjustable in relation to the base means vertically and at the same time in the inclination and in the longitudinal direction of the seat. As a result, the two laterally opposing front connecting levers and the two laterally opposing rear connecting levers form a parallelogram rod assembly between the base means and the seat panel, the dimensions of the front and the rear connecting levers allowing, during pivoting of the connecting levers, the seat panel to be adjusted in relation to the base means from an at least approximately horizontal position in the longitudinal direction of the seat forward and upward and with its rear part downward. At the same time, the backrest is adjusted with its lower part forward and with its shoulder portion backward.

A synchronizing mechanism for office chairs is also known from DE 10 2007 021 782 B3. In this case, a base carrier, on which on the one hand a seat carrier, which is articulated to the base carrier and is pivotable about a transverse axis, and on the other hand a backrest carrier, which is also articulated to the base carrier and is pivotable about a transverse axis, is mounted, is placed on a chair column. The seat carrier and backrest carrier are articulated in such a way that a backward pivoting movement of the backrest induces a downward lowering movement of the trailing edge of the seat.

In DE 36 35 044 A1 a compression spring, which is clamped, for acting on the seat carrier counter to its pivoting direction, between the base carrier and a supporting lever which is pivotable with the seat carrier, is provided as the spring arrangement.

DE 199 22 446 A1 also relates to a synchronizing mechanism for a correlated seat/backrest movement of an office chair.

The previously known items of seating furniture of the aforementioned type have been found to have the drawback that although the seat surface is movable and an ergonomically correct relative position between the seat surface and the backrest can also be set, a relative position, which automatically adapts to these different seat positions, of individual partial regions of the seat surface has in the past not been implemented or taken into account in this regard.

SUMMARY OF THE INVENTION

An aspect of the present invention is to allow a further improved, ergonomically and also orthopaedically advantageous sitting position to be achieved by means of a plurality of elements, which are movable relative to one another, of the seat surface. At the same time, the design complexity required for the implementation should be kept comparatively low.

The invention provides an item of seating furniture in which the frame carries a pelvic support which is arranged in the rear region of the seat surface and is inclined in the working position in relation to the plane of the seat surface, and in which a carrying element of the carrying frame extends into the region of the backrest and carries a thrust bearing on which the frame is supported in a displaceable and pivotably movable manner and the frame is connected, at a trailing end portion of the seat frame, to the seat frame by a joint. The invention starts in this regard from the surprising finding that not only the shaping of the backrest or the displacement of the seat surface leads to an ergonomically and also orthopaedically advantageous sitting position, but also the division of the seat surface into a larger front seat surface region, which at the same time forms the main seat surface, and into a smaller region which is formed by the pelvic support and is at the back, i.e. adjacent to the backrest, allows a significant improvement in sitting posture. In other words, whereas the pelvic support does not perform any particular supporting function in the resting position, it protrudes during a displacement of the working position, supports the pelvis in the process and exerts at the same time a pleasant compressive loading with a forward direction of action, so that the undesirable backward slipping of the buttocks region is prevented. At the same time, this extremely advantageous effect is also achieved in a comparatively simple manner in terms of technology, that is to say in that the pelvic support is immovably connected to the backrest and is pivoted jointly therewith about a horizontal joint extending between the front seat surface region and the pelvic support. A connecting link guide for the frame is thus not required. On the contrary, performing this optimum movement requires merely the joint which not only defines the pivoting movement, but also transmits the sliding movement of the user from the seat surface to the frame, in conjunction with the thrust bearing on which the frame carries out a superimposed pivoting and displacing movement. For this purpose, the thrust bearing is arranged in a plane well above the seat surface. The pelvic support can in this case have both a supporting body, which, like the seat surface, is covered by a common cushion element, and a separate shaped part having a differing degree of hardness. The joint is in this case arranged on both sides of the seat surface and has a common physical or virtual pivot axis. In particular, the joint has just a single degree of freedom.

A particularly advantageous embodiment is also achieved in that the pelvic support is arranged in an upwardly inclined manner exclusively in its working position in relation to the plane of the seat surface. As a result, in the resting position, the pelvic support therefore adjoins the seat surface in a flush manner, so that the seat surface is in principle merely increased in size. As the backrest moves into the front working position, the pelvic support is erected and thus performs the desired supporting function, in a manner comparable to a wedge pillow known per se, as a result of the oblique, backwardly rising shape, so that the pelvis and the loins are automatically tilted forward slightly. This lifts the rib cage and the spinal column is stretched, so that the pelvic and lumbar vertebral region is greatly stress-relieved. It goes without saying that a lowered position of the backrest can additionally be provided in the resting position. Furthermore, the angle of inclination can also be adjustably designed. Depending on the individual preference, the pelvic support can then lie in the resting position in a common plane with the seat surface.

A particularly simple and at the same time extremely effective embodiment is achieved when the pelvic support and the backrest are immovable relative to each other during the movement between the working position and the resting position. Thus, not only the backrest, but also the pelvic support has a supporting effect displacing the user of the item of seating furniture forward. The invention thus overcomes the prejudice of experts that holds that an invariable angle between the seat surface and backrest must be avoided at all costs.

Furthermore, it is particularly expedient if the backrest is immovable relative to the frame during the movement between the working position and the resting position relative to each other, whereas settability of the backrest relative to the frame, including for example in partial portions for generating desired contourings, is conceivable and beneficial.

The frame has a region associated on the one hand with the pelvic support, on the other hand with the backrest. A variant in which the frame has an angular element which is connected by its first leg to the backrest and by its further leg to the pelvic support has accordingly been found to be particularly simple. Both the backrest and the pelvic support can be exchangeably arranged on this angular element. In particular, this provides, irrespective of the aesthetic configuration, an operative mechanism which opens up a large number of areas of application.

Furthermore, a particularly simple configuration of the present invention is achieved when the joint connecting the frame to the seat frame is designed as a hinge joint in order in this way to implement the desired path of movement with low design complexity.

Furthermore, it has in practice proven advantageous if the carrying frame forms a stop for the movement of the backrest into the resting position, so that the backrest rests, in the resting position in which an elevated load acts, not just against the thrust bearing but in addition also against the stop, for example in a form-fitting manner. In addition, the stop, which is inserted into the back of the backrest in a contour-flush manner, stabilizes the lateral introduction of force.

Another, likewise particularly promising modification is provided in that the frame is laterally guided in a guide, in particular in a profile, the frame counteracting in the first place an undesirable lateral displacement, i.e. transversely to the direction of movement of the seat face. In addition, essential bearing elements can in this way also be arranged so as to be protected from external influences. In addition, the guide can also form a sliding path for the frame, so that the guide performs the function of the thrust bearing, and a separate thrust bearing may be dispensed with.

A particularly advantageous configuration of the present invention is achieved when the thrust bearing can be secured in different positions and the distance of the thrust bearing from the seat surface can thus be set. For this purpose, the thrust bearing can be arranged on an adjustable flange which can also be adjusted without tools by means of an adjusting means, for example. Alternatively, the carrying element carrying the thrust bearing can also be designed so as to be able to be set relative to the carrying frame.

A fundamental advantage of the invention also consists in the fact that the complex adaptation to different body weights that was required in the prior art is dispensed with in accordance with the invention. Nevertheless, it has in practice proven to be desirable if the seat surface and/or backrest can be moved into the resting position counter to the restoring force of a spring element, so that the item of seating furniture automatically assumes its upright working position when the user stands up from it. For this purpose, the spring can be designed as a simple coil spring and integrated into the sliding guide of the seat surface.

The thrust bearing can be formed in a simple manner by a mere bearing surface. A modification in which the thrust bearing is designed as a sliding or roller bearing and thus permits at the same time both a displacement of the frame on the thrust bearing and a pivoting movement about the thrust bearing is, on the other hand, particularly expedient. In addition to ball bearings, wheels or rollers, which can also be designed in a profiled manner, as well as sliding bearings, which can preferably have a friction-reducing coating, made of PTFE for example, are also suitable for this purpose.

Furthermore, a development in which the seat frame carries a front seat cushion and the frame carries a pelvic cushion, directly adjoining the front seat cushion, of the pelvic support, thus providing an appealing and high-quality aesthetic appearance, has also proven particularly promising.

The item of seating furniture may be embodied in a broad range of forms. According to a particularly advantageous configuration, the item of seating furniture can be designed as a working chair, office chair, waiting chair, for example in the waiting region of an airport, resting chair or else as the seat of a motor vehicle, aircraft or rail vehicle, as a treatment chair in the medical and therapeutic sector, and also as a hairdressing chair or the like, wherein pure resting armchairs can also advantageously be equipped with the movement kinematics according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention allows various embodiments. In order to further clarify the basic principle of the invention, one of these embodiments is illustrated in the drawings and will be described hereinafter. In the drawings:

FIG. 1 is a schematic side view of an item of seating furniture according to the invention;

FIG. 2 is a schematic plan view onto a carrying frame and also a rotary mount of the item of seating furniture shown in FIG. 1; and

FIG. 3 is a schematic front view of the item of seating furniture shown in FIGS. 1 and 2.

DETAILED DESCRIPTION

The item of seating furniture 1 according to the invention will be described hereinafter in greater detail with reference to FIGS. 1 to 3 which show the item of seating furniture 1 from different views. In order to improve understanding, the cushion elements have in this case not been shown. The item of seating furniture 1 has a carrying frame 2 which is constructed on a rotary frame 3 known per se. This carrying frame 2 carries a seat frame 5 which is horizontally displaceable in a sliding guide 4 between a front working position (illustrated merely by dashed lines) to a rear resting position and has a seat surface 6 which may be seen merely in outline. The seat frame 5, which is displaceable in one plane, is kinematically coupled to a frame 7 which is pivotably movable relative to the seat frame 5 and the carrying frame 2. This frame 7 carries on the one hand a backrest 8, on the other hand also a pelvic support 9 arranged in the rear region of the seat surface 6. For this purpose, the frame 7 has a frame element 10 which is designed as an angled portion and is connected by a first leg to the backrest 8 and by a further leg to the pelvic support 9. As may be seen, this pelvic support 9 is inclined in the working position in relation to the plane of the seat surface 6 and thus protrudes from the plane of the seat surface 6, whereas the pelvic support 9 is lowered in the resting position in relation to the seat surface 6. The mechanism required for these kinematics also comprises a carrying element 11 which is connected to the carrying frame 2, extends into the region of the backrest 8 and is equipped there with a stop 12 for the resting position of the backrest 8. In this region, a thrust bearing 13 for the frame 7 or the backrest 8, which thrust bearing allows a superimposed displacement and also a pivoting movement and is embodied by a roller in the illustrated variant, is arranged on the carrying element 11. The frame 7 is accordingly on the one hand supported on this thrust bearing 13, on the other hand connected at a trailing end portion of the seat frame 5 to the seat frame by a joint 14 designed as a hinge joint, so that an inclination of the backrest from the working position (illustrated by dashed lines) into the resting position leads to an inclination and at the same time to a lowering of the backrest 8, but also to a lowering of the pelvic support 9, which is rigidly connected to the backrest 8, and forward displacement thereof. In this way, the seat surface 6 is also displaced forward on account of the kinematic coupling. For individual adaptation, the thrust bearing 13 can be secured in different positions corresponding to a plurality of recesses 15 selectively receiving a fixing of the thrust bearing 13 in order in this way to be able to set the distance a of the thrust bearing 13 from the seat surface 6. In this way, various ergonomically and orthopaedically beneficial sitting positions are implemented with low mechanical complexity. 

1. An item of seating furniture comprising: a carrying frame having a carrying element; a seat frame having a seat surface; a backrest, wherein the carrying element extends into a region of the backrest; a sliding guide, wherein the seat frame is displaceable in the sliding guide relative to the carrying frame between a front working position and a rear resting position; a pelvic support disposed in a rear region of the seat surface and inclined in the front working position in relation to a plane of the seat surface; a frame configured to carry the pelvic support and pivotably movable relative to the seat frame and kinematically coupled to the seat frame; a thrust bearing configured to support the frame in a displaceable and pivotably movable manner, wherein the carrying element is configured to carry the thrust bearing; and a joint connecting the frame to the seat frame at a trailing end portion of the seat frame.
 2. The item of seating furniture as recited in claim 1, wherein the pelvic support is disposed in an upwardly inclined manner in the front working position in relation to the plane of the seat surface.
 3. The item of seating furniture as recited in claim 1, wherein the pelvic support is disposed in the rear resting position in a common plane with the seat surface.
 4. The item of seating furniture as recited in claim 1, wherein the pelvic support and the backrest are immovable relative to each other during a movement between the front working position and the rear resting position.
 5. The item of seating furniture as recited in claim 1, wherein the backrest is immovable relative to the frame during a movement between the front working position and the rear resting position relative to each other.
 6. The item of seating furniture as recited in claim 1, wherein the frame includes an angular element having a first leg and a second leg, wherein the angular element is connected to the backrest by the first leg and connected to the pelvic support by the second leg.
 7. The item of seating furniture as recited in claim 1, wherein the carrying frame includes a stop for stopping a movement of the backrest into the rear resting position.
 8. The item of seating furniture as recited in claim 1, wherein the frame is guided in a guide.
 9. The item of seating furniture as recited in claim 8, wherein the frame is guided in a profile.
 10. The item of seating furniture as recited in claim 1, wherein the thrust bearing is securable in different positions.
 11. The item of seating furniture as recited in claim 1, wherein the thrust bearing is one of a sliding and a roller bearing.
 12. The item of seating furniture as recited in claim 1, wherein at least one of the seat surface and the backrest is movable into the rear resting position counter to a restoring force of a spring element.
 13. The item of seating furniture as recited in claim 1, wherein the seat frame is configured to carry a front seat cushion and the frame is configured to carry a pelvic cushion of the pelvic support directly adjoining the front seat cushion.
 14. The item of seating furniture as recited in claim 1, wherein the item of seating furniture is one of a working chair, an office chair, a waiting chair and a resting chair. 